Title:
EYE-PROTECTION DEVICE HAVING DUAL HIGH VOLTAGE SWITCHING
Document Type and Number:
WIPO Patent Application WO2005017636
Kind Code:
A3
Abstract:
An auto darkening eye protection device comprising a shutter assembly and a control circuit. The shutter assembly is adjustable between a light state and a dark state. The control circuit comprises a sensing circuit, a weld detect circuit, a positive voltage generator, and a negative voltage generator. The sensing circuit senses incident light and provides an output indicative of the incident light. The weld detect circuit receives the output of the sensing circuit, and enables a dark state drive signal to be delivered to the shutter assembly. The positive and negative voltage generators output the dark state drive signal to the shutter assembly to switch the shutter assembly from the light state to the dark state upon enablement by the weld detect circuit. The dark state drive signal includes a high voltage pulse followed by a stable AC waveform. The high voltage pulse is formed by a positive voltage signal and a negative voltage signal.
Inventors:
HAMILTON THOMAS J (US)
Application Number:
PCT/US2004/026039
Publication Date:
September 22, 2005
Filing Date:
August 11, 2004
Export Citation:
Assignee:
HAMILTON THOMAS J (US)
International Classes:
G02F1/1335; G09G5/00; H01J40/14; G05F; (IPC1-7): H01J40/14; G02F1/1335
Foreign References:
| US5252817A | 1993-10-12 | |||
| US5880793A | 1999-03-09 |
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